Airplane wing rib construction



Feb. 1 4, 1939; K. SCHMIDT AIRPLANE WING RIB CONSTRUCTION Filed March 9, 1938 KARL SCHMIDT ATTDRNEY Patented Feb. 14, 1939 UNITED STATES PATENT OFFICE 2,146,768 AIRPLANE WING RIB CONSTRUCTION Karl Schmidt, United States Navy Application March 9, 1938, Serial No. 194,887

8 Claims.

(Granted under the act of March 3, 1883, as amended April 30, 1928 3'70 0. G. 757) at intervals. In this method the fabric cover is stretched over the airfoil frame in contiguous relation to the capstrips of the rib members after which the usual reenforcing' tape of a width equal to 'the capstrip is placed on the cover over the entire length of the capstrip and the two secured thereto by the lacing cord which is loopedv tightly around the capstrip at intervals.

The principal object of this invention is the provision of an airplane wing r'ib which is so constructed that the fabric covering may be attached thereto continuously throughout the entire length of the rib, thus avoiding localized strains and insuring that the covering is stretched tightly with evenly distributed tension so that the full strength of the cover fabric may be developed.

Another object of the inventionvis the provision of an airplane wing rib and a cooperating cover fastening device by means of which the fabric covering, when attached to the wing, will present a smooth cambered surface of high aerodynamic efficiency.

A further object of the invention is to provide means of attaching the fabric wing covering continuouslyover the full length of the airplane wing rib, the fabric covering neither being cut nor pierced with holes to effect the attachment.

With these and other objects in view, as well as other advantages that may be incident to the use of the improvements, the invention consists in the parts and combinations thereof hereinafter set forth and claimed, with the understanding that the several necessary elements constituting the same may be varied in proportion and arrangement without departing from the nature and scope of the invention, as defined in the appended claims.

In order to make the invention more clearly understood, there are'shown in the accompanying drawing, means for carrying the invention into practical use, without limiting the improvements in their useful application to the particular construction, which, for the purpose of explanation, have been made the subject of illustration.

In the accompanying drawing:

Fig. 1 is a vertical transverse sectional view through a capstrip constructed in accordance with the invention and illustrating the manner in which the locking strip and fabric is positioned therein;

Fig. 2 is a similar 'view showing the'lock strip in its final or fabric securing position; and

Figs. 3 to 6 are similar views of different forms of the invention.

Referring to the drawing and particularly to Figs. 1 and2 thereof, thecapstrip of a rib or other frame structure embodying the invention, is shown as comprising two channel members I0 having inner flanges II terminating in inwardly extending parallel flanges I2 secured together by rivets I3 and outer flanges I4 terminating in oppositely curved edges I5 which constitute the support for the fabric covering I6. The fabric I6 is secured between the channel members III by means of a locking strip I'I' while the fabric is under an initial tension. The load-strip I1, being of greater width than the space between the flanges I4, it is tilted slightly, as indicated in Fig. 1, after which it is leveled and drawn outwardly by the fabric until the latter is gripped firmly between the locking strip and the flanges I4, as shown in Fig. 2. The channel members II] are clamped together by means of self-tapping screws I8 which are threaded into a tapping plate I9. The opening between the flanges I4 is covered by tape 20 which is dope cemented to the fabric I6 so as to provide a smooth surface of low wind drag.

The capstrip structure shown in Fig. 3 is substantially the same as that above described with the exception that the tape 20 is omitted and a metal load-strip 2| secured in the space between the flanges I4 by screws 22 threaded into the looking strip I1.

In Fig: 4 a capstrip structure is illustrated which is quite similar to that shown in Fig. 3 except that the clamping bolt I8 is omitted. In this 0 construction the channel members I0 are prevented from separating under strain by forming the locking strip II with outwardly curved edges 23 which interlock back of inwardly curved edges 24 formed on the outer flanges I4 of the channel members I0. Also, in this construction the locking strip I1 is formed with a longitudinal rib 25 which extends outwardly between the inwardly curved edges 24 of the flanges I4 for abutting engagement by the load-strip 2i.

Figs. 5 and 6 show a construction in which the capstrip is formed with a channel 26 on one side thereof having inner and outer laterally extending flanges 21 and 28, the former merging into an inwardly extending flange 29. The channel 28 55 is normally closed by a resilient plate 30 which is secured to the flange 29 by rivets 3 I. This plate is formed with a laterally extending outer flange 32 which cooperates with the outer flange 28 in providing a supporting surface for the covering ll. In securing the covering I3 to the capstrip, the plate 30is flexed laterally as shown in Fig. 5 and the covering l6 forced into the channel 26 by a locking member in the form of a rod 33 after which the plate 30 is clamped in the position shown in Fig. 6 by self-tapping screws 3 which are threaded into a tapping plate 35. The sealing tape 20 is next cemented to the covering and the entire surface applied with the usual dope varnish.

The structures hereinabove described may be further modified in proportion and arrangement of the parts by those skilled in the art without departing from the nature and scope of the invention as defined in the appended claims.

The invention described herein may be manufactured and/or used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

I claim:

1. An airplane wing rib" construction comprising a capstrip to which a covering is adapted to be secured, said capstrip embodying a channel member having overhanging flexible side flanges, a locking strip disposed within said channel beneath said overhanging flanges for gripping the covering therebetween and beneath which the covering extends when gripped thereby,- and means for clamping said flanges together to maintain said locking strip against'displacement.

2. An airplane wing rib construction comprising a capstrip to which a covering is adapted to be secured, said capstrip embodying a channel member having overhanging side flanges, a lockin strip disposed within said channel-beneath said overhanging flanges for gripping the covering therebetween and beneath which the covering extends when gripped thereby, and a load-strip disposed between said flanges and secured to said locking strip.

3. An airplane wing rib construction comprising a capstrip to which a covering is adapted to be secured, said capstrip embodyinga channel member having overhanging flexible side flanges, a locking strip disposed within said channel beneath said overhanging flanges for gripping the covering therebetween and beneath which the covering extends when gripped thereby, means for clamping said flanges together to maintain said locking strip against displacement, and a loadstrip disposed between said flanges and secured to said locking strip.

4. An airplane wing rib construction comprising a capstrip to which a covering is adapted to .be secured, said capstrip embodying a channel member having inwardly and downwardly extending side flanges, and a locking strip disposed within 5 said channel and having upwardly extending edges for interlocking engagement with said side flanges to grip the covering therebetween and beneath which the covering extends when gripped thereby. 10

5. An airplane wing rib construction comprising a capstrip to which a covering is adapted to be secured, said capstrip embodying a channel member having inwardly and downwardly extending side flanges, and a locking strip disposed within said channel and having upwardly extending edges for interlocking engagement beneath said 'side flanges to grip the covering therebetween and beneath which the covering extends when gripped thereby, said locking strip being formed with a longitudinal rib disposed between said side flanges.

6. An airplane wing rib construction comprising a capstrip to which a covering is adapted to be secured, said capstrip embodying a channel member having inwardly and downwardly extending side flanges, a locking strip disposed within said channel and having upwardly extending edges for interlocking engagement beneath said side flanges to grip the covering therebetween and beneath which the covering extends when gripped thereby, and a load-strip disposed between said flanges and secured to said locking strip. e

'7. An airplane win'g rib construction comprising a capstrip to which a covering is adapted to be ll secured, said capstrip embodying a channel member having inwardly and downwardly extending sideflanges, a locking strip disposed within said channeland having upwardly extending edges for interlocking engagement beneath .said side 0 flanges to grip the covering therebetweenand beneath which the covering extends when gripped thereby, said locking strip being formed with a longitudinal rib .disposed between said side flanges, and a load-strip secured to said rib. 5

8. An airplane wing rib construction comprising a capstrip to which a covering is adapted to be secured, said capstrip having a channel formed in one side thereof, a locking strip disposed within said channel beneath which the covering extends, a flexible plate secured to said capstrip and extending over said channel for confining said locking strip and covering within said channel, and means for clamping said flexible plate to said channel to prevent the displacement of said locking strip and covering from said channel.

KARL 

